Mystery Hot Water Leak???

Hi, for the past 2 week, I recently noticed a soft 'hissing' sound in the downstairs bathroom, it's not really hissing, it's a constant pssssshhhhhhhhhhhhhhhhhhhh sound. I looked around for the sound and put my ear near the wall, toilet and sink and the sound is loudest near the drain pipe of the sink.

When I go into the kitchen, there is a large warm spot 5 feet by 5 feet. I have wood floors. Our entire floor was replaced last year and a moisture barrier was put between the cement and the wood flooring when it was glued down. I don't see any indication of the wood being wet or wet spots coming through the joints of the wood, but it seems the warm spot is slowing increasing in size every couple of days.

I went outside to check the water meter, and if there was a leak, wouldn't that triangular thing be spinning? I stared at it for 2 minutes and it didn't move a bit.

Also, prior to this happening, whenever we would turn on the kitchen sink hot water or the upstairs bathroom sink hot water or upstairs shower hot water, it would take literally 45-60 seconds before any warm/hot water started coming through. Now, it's almost instantaneous, like within 5 seconds!

A slow leak may take longer than a couple of minutes to show up on the meter...you might note its position, don't use any water for maybe an hour (or overnight), then look at it to see if it has moved.

Well the last time I checked the water meter when it wasn't moving was probably 5 days ago. I did leave it for several hours before and the triangle thing didin't budge.

Anyway, I checked it this morning and it's moving now, so perhaps if it's a leak and it got bigger now.

What is the 'psssssshhhhhh' sounds i hear near the bathroom sink drain pipe? If that's a hole in a pipe and I can hear it through the walls, woudln't that indicate a big leak? I wonder where all the water is going?

Parts of the garage concrete floor are also warm.

I didn’t notice any water marks trying to escape through the joints between the wood floor boards. I know a moisture barrier substance was put between the concrete floor and the wood floor when it was installed. If it there is a slab leak, would the water be between the concrete and the moisture barrier, or would it eventually penetrate the moisture barrier and go between the surface of the moisture barrier and the bottom of the wood flooring ultimately trying to escape through the joints?

If the leak is below the slab, you may not notice anything in the house. But, some of those leaks can end up being VERY costly.

There are a couple of choices...you either chop up your slab to find the problem and fix it (but realize if there's one leak now, there may be more coming soon after), or you abandon the line entirely and replumb it above the slab. There are leak detector companies, and a good one can localize the leak to minimize chopping up the slab, but again, if you have one leak under the slab, you'll probably have more. Where and how to do that depends on your house and the layout.

I had a friend come over that is the building maintenance manager at a large condo complex. Anyway he mentioned it's likely a slab leak below the slab and it was surprising that we didn't see any evidence of any water coming through the wood floor or around the corners of the wall or anything. He thought a re-route might be the best option (hopefully that's an option) and found the three manifolds where the plumber would do the re-route i guess. Have to find the leak first and see which pipe it's coming from. It doesn't look like any damage has occurred, so I don't think insurance can get involved if there is no damage. He said there might not be any damage and the warm floor we're feeling is because the hot water leak under the slab is heating up the concrete which is heating up the bottom of the floor, but didn't come through. We ran a mositure meter on top as well and it doesn't show any higher percentage of wetness than another part of the floor 15 feet away that's dry. So hopefully there is no damage or what not. I wonder where all that water leaking went then?

By the time the leak gets bad enough to give you water on the floor, it will be leaking so badly that the water heater will lose the hot water as fast as it heats it, so you will ONLY have cold water. Some home owner's insurance companies will cover the costs of locating and accessing the leak, (which is why I call a leak locating company, and less your deductible), but NOT the actual repair of the pipe, while others, such as Allstate, won't do it until you actually have water on the floor causing damage.